This is slightly different then you need, becauase i`m looping clip too(was doing animated grass clips)but good to get you going. In your case i would create a short clip, with no loop, then instance and manage the offsets.
this is 60 frames clip for 360 spin with random offset….
Attachments in this post:
http://fx-td.com/houdiniandchill/wp-content/uploads/discord/20250304/10/25/usd_clip_example.hip
http://fx-td.com/houdiniandchill/wp-content/uploads/discord/20250304/10/25/image.png
http://fx-td.com/houdiniandchill/wp-content/uploads/discord/20250304/10/25/Instancer_anim.mp4
